This disclosure relates to a power generating system. In particular, the disclosure relates to an overvoltage monitor and prevention configuration that is separate from a generator control unit of the power generating system.
One type of aircraft electrical power generating system includes a variable frequency generator. The variable frequency generator includes a permanent magnet generator (PMG), an exciter, and a main generator mounted for rotation on a common shaft. The shaft is driven by a prime mover.
A generator control unit (GCU) converts alternating current from the PMG to provide DC current to the exciter. Current from the exciter is fed to the main generator, which produces a voltage output.
Under some conditions, an overvoltage condition may result, which produces a higher than desired output voltage from the main generator. The main output of the generator main stator may be referred to as a primary current. There are many strategies for limiting or preventing overvoltage conditions, but desired overvoltage protection remains lacking. A typical overvoltage management strategy relies on the generator control unit to monitor power supplied by the main generator, and simply trip a switch to an open condition once an overvoltage threshold has been reached. In one example, manufacturing defects or environmental effects simultaneously disable the GCU and cause abnormally high generator output values. The disabled GCU is unable to detect or react to these high output values.